Solar power has the great benefit of being able to be installed in a wide variety of places, from large solar farms to residential rooftops, from floating on top of reservoirs to highway noise barriers. Wind power, unfortunately, is mostly limited to large swaths of land or offshore.
This is due to the fact that wind turbines need to be high in the air to reach the higher-speed winds, and in order to harness those winds, the blades need to be large. Also, wind turbines face greater NIMBYism than solar panels from people who think they're an eyesore or too loud.
A new study says that there is another option than just large wind farms in the middle of nowhere: viaducts. The long bridge structures are typically high off of the ground and usually contain a series of arches within which wind turbines could be built.
Researchers from Kingston University in London used a viaduct in the Canary Islands for reference in computer models and simulations that showed that the wind blowing between the pillars on these infrastructures can move wind turbines and produce energy. The construction of these wind generators within viaducts could bring renewable energy to heavily built-up territories with little room for wind turbines or natural areas that have limitations placed on construction.
The researchers ran simulations with different-sized turbines to see what configuration would be most efficient.
"As natural, the more surface is swiped by the rotor, the more power can be produced; however, it was seen that in small turbines the power rate per square meter is higher," explains Oscar Soto, one of the researchers.
The team ultimately determined that two medium-sized turbines would be the most viable combination in the Juncal Viaduct, in Gran Canaria. That combination of two 0.25 MW turbines would have an output that would be equal to the energy consumption of 450-500 homes, based on average consumption in the area. It would avoid the emission of 140 tons of CO2 per year.
This study is not the first time this idea has been considered. A competition to give viaducts in Italy a green makeover got a lot of press a few years ago when a leading entry proposed wind turbines between the pillars. The study is important though because it pushes the idea forward and shows that the application would actually work and areas with little space to offer could still add wind power to the renewable energy mix.